This invention relates generally to improvements in optical diffraction gratings, and more particularly to improved optical diffraction gratings for high energy laser applications.
Diffraction gratings are essential for effective beam tuning for high energy laser systems. These gratings conventionally comprise, for example, thin disks of silicon or the like, engraved with precision rulings to provide a surface having the desired grating pattern of finely spaced, shallow grooves. The shape, depth and pattern of the grooves characterize the performance of the grating. Use of the gratings often results in deterioration or other damage to the grooves comprising the grating. Cleaning or otherwise salvaging a deteriorated grating is extremely difficult, and it usually must be returned to the manufacturer for refurbishing. Since conventional gratings are ruled, etched, or engraved into the faceplates of, or integral with, a heat exchanger or other supporting structure, the number of times a grating may be refurbished is limited, and, upon expiration of the usefulness of the grating, the substantially more expensive heat exchanger structure may have to be sacrificed. Further, cooling channel distortions in the grating surface which may be polished out of a mirror surface having similar supporting structure may not be removed from a conventional grating configured integrally with the heat exchanger or other substructure.
The novel replaceable diffraction grating of the present invention is configured to be disposable and replaceable, thereby avoiding the need for the substantially more expensive conventionally used device. The novel configuration for the grating of the present invention may be provided of single crystal silicon disk up to about 12 inches (30.48 centimeters) in diameter, and can be removeably held to a heat exchanger/substrate assembly by vacuum. The novel configuration of the present invention obviates the consideration of closely matching the thermal properties of the grating and substructure materials. Replacement of a deteriorated grating is thereby greatly facilitated, resulting in substantially less downtime for replacement as compared to that necessary to replace conventionally configured grating devices. In addition, the novel grating of this invention may include means to quickly and conveniently align the replaceable grating.
It is, therefore, an object of the present invention to provide an improved optical diffraction grating for high energy laser systems.
It is a further object of the present invention to provide an improved high energy laser diffraction grating which is disposable and easily replaceable in the laser system.
These and other objects of the present invention, as might occur to one with skill in the field of this invention, will become apparent as the detailed description of a representative embodiment thereof proceeds.